Taking into consideration environmental requirements and profitability, PET bottles or glass bottles have been collected and recycled. Upon recycling, labels having printed product names, components and other figures excluding the bodies of PET bottles or glass bottles have to be separated and removed from the bottles. In particular, the paper labels that have mainly been used to date are removed using industrial water. Specifically, the collected PET bottles or glass bottles are immersed in industrial water at about 80° C. containing caustic soda to remove the labels therefrom. Thereby, recycling of the bottles generates environmental wastewater, which is subject to environmental regulations.
Therefore, the demand for film labels, not paper labels, is increasing.
An example of a film usable as a label includes a polyvinyl chloride-based film, which undesirably causes environmental problems such as the generation of dioxin upon incineration, etc. Accordingly, a heat-shrinkable polyester-based film is receiving attention as a replacement for the paper labels.
A heat-shrinkable polyester-based film may be utilized as a label by printing the film in the form of a sticker or as in a conventional paper label and attaching the film using an aqueous adhesive.
Compared to typical PET bottles or drink bottles, PET bottles or glass bottles used for liquor purposes mainly get their color from a pigment, a UV block, and other additives that are mixed in to minimize the denaturation of the contents of the bottle.
In order to make the advertisement effects that are shown using a film label on such bottles more obvious, the back surface of the printed film label may be subjected to back coating using white ink or the like. In this case, however, coating effects are small and the color of the bottle is projected as is, undesirably decreasing advertisement effects. As such, two or more back coatings are required, which undesirably decreases processability and productivity.
Also when a label is adhered using an adhesive, an adhesive is applied onto a bottle using gravure printing or the like, and thus a mark formed by applying the adhesive is present in the form of a band. Although the paper label may hide such an adhesive mark, the heat-shrinkable film has low hiding capacity and thus such a mark is projected as is, undesirably decreasing advertisement effects.